The problems associated with diseases which affect the human central nervous system such as Parkinsons disease, multiple sclerosis, muscular dystrophy and strokes produce various ailments that include orthopedic or musculoskeltel pain such as patello-femoral pain and post-operative hip pain, muscle spasms, disuse muscle atrophy, post-operative venous thrombosis, spasticity, poor blood circulation, ataxia and various other acute and chronic pain. To treat these and other related medical ailments, there are two dominant electronic, nerve stimulation devices in use: a transacutaneous electrical nerve stimulation (TENS) device and a neuromuscular stimulation (NMS) device. The TENS devices are utilized to mask pain signals in a human body before the signals reach the brain, thus, giving a patient apparent relief from the pain.
The prior art NMS devices produce electrical d-c pulses that are applied to the skin of a patient by one or more electrodes. The electrodes are placed over the muscle to be stimulated in order to activate or contract the muscle. The timing characteristics of the applied pulses are usually predetermined by the prescribing doctor or they may be individually selected or controlled by switches available to be operated by the patient.
The pulses produced in the prior art are in the range of 100 to 300 microseconds and are applied as either a continuous pulse train as typically used in the TENS device; or as repetitive pulse trains that range between 1,000 to 15,000 milliseconds as typically used in the NMS devices. The TENS devices provide only transient benefits from pain. Thus, within minutes after stopping a TENS device, the effect is diminished. Also, the pulses used in the prior art NMS devices are at a relatively high intensity that produce powerful muscle contractions. In contrast, the device of the instant application does not cause powerful contractions but rather produces very brief twitches of the muscle and smaller movements of the joint. This application technique helps to decrease disuse atrophy, to improve a joint range of motion and to decrease pain for prolonged periods of time.
The instant application further differs from the prior art devices in that the individual pulses are in the range of 30 to 50 microseconds, are preset and are applied in some cases in partially overlapping pulse trains having overlaps that range between 20 to 50 milliseconds. The overlapping trains are specifically timed to take advantage of neurologic enhancement and/or inhibition either of which increase coordination and strength or decrease excessive muscle tone or spasms. The overlapped pulses are particularly intended to follow the naturally or physiologically occurring co-contraction of opposing muscle which produces joint stabilization as the limb rapidly changes direction. Also, the results achieved by the instant invention are either immediate or may not begin to take effect unit the day after multiple applications. Thus, long lasting pain relief of up to a few weeks has been achieved.
A search of the prior art did not disclose any patents that read directly on the claims of the instant invention, however the following U.S. Pat. Nos. are considered related:
______________________________________ U.S. Pat. No. INVENTOR ISSUED ______________________________________ 4,926,865 Oman 22 May 1990 4,926,864 Dufresne et al 22 May 1990 4,622,973 Agarwala 18 November 1986 4,392,496 Stanton 12 July 1983 4,340,063 Maurer 20 July 1982 ______________________________________
The U.S. Pat. No. 4,926,865 Oman patent discloses a microcomputer-based transcutaneous electrical nerve stimulation (TENS) device that controls pulse duration, pulse repetition rate, stimulation duty cycle, and modulation of pulse parameters. The device may be used either for pain relief or to facilitate muscle contractions. The intensity of the stimulation is determined by the amplitude and duration of the individual pulses, while the pulse rate determines the perceived continuity of the applied stimulation.
The U.S. Pat. No. 4,926,864 Dufresne et al patent discloses a microcomputer-based transacutaneous electrical nerve stimulation (TENS) device. The device operates from a 3-volt battery that is applied to a step-up voltage circuit to create a high-voltage level energy source that is applied to a patients skin. The step-up voltage circuit stores and subsequently supplies a plurality of amplitude timing signals to an output circuit from where the timed signals are applied to a patient's skin to mask pain signals before they reach the brain.
The U.S. Pat. No. 4,622,973 Agarwala patent discloses a neuromuscular stimulation (NMS) device that causes muscle to contract by applying to a patient's skin a plurality of programmable electrical pulses. The device is typically used therapeutically when there is a lack of neuro-motor faculty, or when muscles have become weakened or damaged by disease or trauma.
The U.S. Pat. No. 4,392,496 Stanton patent discloses a neuromuscular stimulator device which provides external electrical stimulus induced muscle exercise to retard or prevent tissue atrophy. The device provides, on two output channels, alternating pulses through electrodes that connect to a patient's skin. The applied pulses are increased in intensity at a variable rate until a prescribed fixed intensity is reached. The pulses are also applied during an adjustable predetermined stimulation interval and removed during a resting interval which occurs alternately. The amplitude limit of the pulse is adjustable by a patient within an upper limit established by a clinician at the time the device is set up for the patient.
The U.S. Pat. No. 4,340,63 Maurer patent disclose a stimulation device that electrically stimulates living tissue, including body organs, muscles and nerves. The device produces a series of pulses that are applied to the surface of the body or invasively implanted in the body. The device includes an electrical circuit that includes a control for varying the pulse width, stimulus intensity, pulse repetition rate, and the on-time of the pulse to vary the pulse width. The pulse width variation is dependent upon the optimal pulse width desired for a particular nerve tract or bundle. The applicant's device does not vary the pulse width or the pulse repetition rate.
for background purposes and as indicative of the art to which the invention relates reference may be made to the patent issued to:
______________________________________ U.S. Pat. No. INVENTOR ISSUED ______________________________________ 5,133,354 Kallok 28 July 1992 5,097,833 Campos 24 March 1992 5,070,873 Graupe et al 10 December 1991 4,976,264 Petrofsky 11 December 1990 4,832,033 Maher et al 23 May 1989 4,642,769 Petrofsky 10 February 1987 4,480,830 Petrofsky et al 6 November 1984 4,324,253 Greene et al 13 April 1982 4,147,171 Greene et al 3 April 1979 4,817,254 Maurer 18 June 1974 ______________________________________